344 ORDERS OF FISHES. 



feet, but its average length is about three feet. The Barra- 

 munda " is eel-shaped, but considerably shorter and thicker 

 than a common eel, and covered with very large scales. The 

 head is flattened and broad, the eye lateral and rather small, 

 the mouth in front of the broad snout and moderately wide. 

 The gill openings are a rather narrow slit on each side of the 

 head. There are no external nostrils. The tail, which is of 

 about the same length as the body without the head, is com- 

 pressed, and tapers to a point, but it is surrounded by a very 

 broad fringe, supported by innumerable fine and long fin-rays. 

 There are two fore and two hind paddles, similar to each other 

 in shape and size, and very different from the fins of ordinary 

 fishes ; their central portion being covered with a scaly skin, 

 and the entire paddle surrounded by a rayed fringe. If we 

 were to cut off the hind part of the tail of a fish, the piece 

 would bear a strong resemblance to one of the paired paddles. 

 The vent is situated in the median line of the abdomen be- 

 tween the paddles. 



" In order to obtain a view of the inside of the mouth, it is 

 necessary to slit it open, at least on one side. We then notice 

 that there are a pair of nasal openings within and on each side 

 of the cavity of the mouth. The palate is armed with a pair 

 of large, long, dental plates, with a flattish undulated and 

 punctated surface, and with five or six sharp prongs on the 

 outer side, entirely similar to the fossil teeth described under 

 the name of Ceratodus. Two similar dental plates of the lower 

 jaw correspond to the upper, their undulated surface fitting 

 exactly to that of the opposite teeth. Beside these molars, 

 the front part of the upper jaw (vomer) is armed with two 

 obliquely placed incisor-like dental lamellae, which have no 

 corresponding teeth in the lower jaw. As we know the kind 

 of food taken by the Barramunda, the use of these teeth is 

 apparent. The incisors will assist in taking up or even tear- 

 ing off leaves, which are then partially crushed between the 

 undulated surfaces of the molars. 



" The skeleton consists of a cartilaginous basis, in the form 

 of a long tapering chord for the body and tail, and in that of a 

 capsule for the head. No segmentation into separate vertebrae 

 is visible in any part of the notochord ; but it supports a con- 

 siderable number of apophyses, the abdominal of which bear 

 well-developed ribs, all being solid cartilaginous rods, with a 

 thin sheath of bone. In the same manner no part of the brain- 

 capsule is ossified, but it is nearly entirely enclosed in thin 

 bony lamellae. This is also the structure of the appendages of 

 the skull, as the mandible and the hyoid and scapulary arches. 



